Carburetor



C. SCHMID Dec. 10, 1935.

CARBURETOR Filed March 9, 1931 3 Sheets-Sheet 1 WWW/5???? V w V ME C. SCHMID CARBURETOR 3 Sheets-Sheet 2 Filed March 9, 1931 (14 .0: vmM

C. SCHMID Dec. 10, 1935.

CARBURETOR Filed March 9, 1951 3 Sheets-Sheet 3 -'of service, that is to make the mixture poorer at movement of the throttling element.

Patented Dec. 10, 1935 2,023,647

UNITED STATES PATENT OFFICE OABBUBE'IOR Carl Schmid, Berlin-Charlottenburg,

Application March 9, 1931, Serial No. 521,315

In Germany March 15, 1930 15 Claims. (c1. 261-12) It is known that in internal combustion engines adapted to operate under varying load the problem of adapting the operation of the carburetor to the changing load conditions presents many difliculties, particularly the proceedings when supplying the mixture and shutting off the supply are very different. Carburetors have obvious been designed in the first place for the conditions of services during the supplying of The device may be made in such a manner that it can be subsequently mounted on existing carburetors, or it can be incorporated with the carburetor in manufacture. a

The mixture supplied to the internal com- 5 bustion engine comprises air and fuel; hence the mixture can be enrichened or weakened by altering either the fuel or air supply. There exist principally four possibilities for carrying out the the mixture, 1. e. when good motor emciency is invention: 10 required. Itis further a known fact that when (l) Altering the pressure within the fuel the mixture supply is being shut oif,the carchamber or float chamber,

buretor supplies an unnecessarily rich fuel mix- (2) Alterlngthe cross section of the channel ture, whereby much fuel is lost which might be through which the fuel is supplied from the fuel saved. It is further evident, that, when a vechamber tothe induction pipe, l5

'(3) Altering the quantity of correction or supplemental air introduced into the fuel channel. which connects the fuel chamber and the fuel nozzle,

(4) Introducing additional air into the induc- 20 tion pipe at a point beyond the fuel nozzle.

, Several embodiments of theinvention are illustrated diagrammatically by way of example partly for subsequent fitting :on existing carburetors and partly for incorporation at the orig- 25 in'al manufacture of said carburetors.

Fig. l is a side view partly in section showing an arrangement designed to be applied to existing carburetors in order to influence the mixture by means of vacuum in the float chamber. 30

1A is a sectional view showing a modified detail applicable to Fig. l.

- Fig. 2 is a sectional-view showing a detail of an induction pipe connection applicable to the embodiment of Fig. l. v

Fig. 3 is a view partly in section showing a further modification applying the principles of Fig. l in the original construction of a carburetor. L

' Fig. 3A is a side view partly in section of the 40 embodimentofl'imS. i

Fig. 4 isasideviewpartlyinsectionofafurthe: modification showing adevice foraltering the mixture by total or partial throttling of the 45 supply conduit to the fuel nomle.

Fig. 4A shows a side view partly in section of the embodiment of Fig. 4.

Fig. 4B is a plan view partly in section on line IVB 0! P18. 4.

Pig. 5 is an elevation partly broken away and partly in section on line H of Fig. 5A of afurther modification in which the alteration of the mixture is accomplished by means of correction or supplemental air. I 55 hicle driven by the engine has accelerated to a certain speed, only a fraction of the motor ciliciency is required for maintaining the speed, and the mixture therefore may be much poorer than while accelerating.

This invention has for its object to automatically vary the mixture according to the condition the moment when shutting off the supply starts when thefull engine efliciency is not required, and to reestablish the normal condition of mixture when the turning on of the supply starts. By the improvement according to the invention, not only much fuel is saved but the combustion elements, such as spark plugs, valves, compression chamber and so forth, are protected against sooting, and the piston and the cylinder working surfaces are. protected against premature wear. The invention permits an engine operator who attaches importance to the great elasticity of the motor, to adjust the carburetor for rich charge without fouling of the motor as would occur without the device according to the invention, as this .devicerestricts the fuel content of the mixture during theshutting ofl. of the mixture supply.

All suggestions and auxiliary arrangements produced hitherto realize, with a certain carburetor adjustment, only one and the same composition of the mixture, whereas the main feature of the present invention is, that by the same and with one and the same position of the throttling element, actually two cliflerent mixture compositions are automatically obtained, that is a mixture poorer in fuel if the position in question of the throttle element is attained by a closing movement, and a mixture richer in fuel if the position is attained by an opening movement. This mixture alteration can take place either prior to or at the same time and more rapidly with the tom actuating the throttle valve.

Fig. 5A is a side .view partly in section of the embodiment of Fig. 5.

Fig. 6 is a sectional view showing a detail of a modification of the embodiment of the invention according to Fig. 1.

Fig. 1 illustrates a carburetor which comprises an air conduit or induction pipe A, a fuel nozzle B, a venturi C, a throttle valve D and a float chamber E which is connected with the induction pipe through nozzle B and conduit F. So far as these parts are shown in the other figures of the drawings they are referred to by similar reference characters.

In Fig. 1 the control is illustrated by way of example as a piston valve built in the rod sys- At the shutting offv of mixture, the piston l first moves towards the left in the drag mechanism comprising cylinder 2 up to the end of the cylinder which acts as a stop. Only then does the movement of the throttle valve commence. By this initial movement of the piston l the suction conduit of the carburetor is connected with the upper portion of float chamber E by a conduit comprising tube 3, a cut-out portion lb in the control piston, and a tube 4. The surface of the liquid fuel is thereby placed under a certain vacuum. The degree of vacuum is adjusted by means of an equalization opening 5 in cylinder 2. For supplying a richer mixture for heavier engine load the piston l first moves toward the right in the cylinder 2 and closes the communication just mentioned and. only then does the throttle valve again move.

The throttle valve is prevented' from carrying out an automatic to and fro movement by a light brake arrangement 6.

As shown in Figs. 1-2 the tube 3 of the mixture control conduit is connected to a nipple 8 provided with a screw socket 9 which engages the tubular hollow shaft of the nozzle '1. The nozzle 1 is provided with a plurality of superposed branch passages 1b. The plurality of branch passages are provided for the following reason:

If only one passage were provided (see nozzle III in Fig. 1A) terminating in close proximity to the throttle. valve, a very high vacuum would be created within the float chamber, if-

the throttle after a closing movement were kept slightly open, this being due to the high velocity of the mixture stream through the small passage left open by the throttle. This vacuum would be so high that the fuel supply might be entirely interrupted.

If, however, the passage of the nozzle I were arranged far away from the throttle, the vacuum in the float chamber would be too small and practically without influence upon the fuelsupply if the throttle valve after a closing movement were kept slightly open.

In order to avoid these disadvantages, the nozzle I and'its passages must be arranged in a definite position with regard to the throttle valve and this definite position can only be determined by calculation or by tests. 7

-The mentioned disadvantages are, however, overcome more easily by providing a plurality of superposed passages lb which are connected to a common passage in which the vacuum existing in the several passages produces an average vacuum which may be transmitted into the float chamber.

Figs. 3 and 3A show an arrangement in which the drag mechanism shown in -1 is combined with the carburetor in the original construction of the carburetor. In this case a mixture control air conduit is provided and comprises superposed members or channels 1b in the wall of the induction pipe terminating in a common passage Ia which connects with the passage 8a. The outer end of passage 8a is covered by a drag mechanism comprising segment l5 which is loosely mounted on the shaft of the throttle valve. This segment has a boring l6 termi- 1 nating in a nipple I! which is connected by a flexible pipe l8 with a connection 19 of the float chamber E. The throttle control lever 20 has a spring mechanism 2| which presses against the segment l5. During the to and fro movement 15 of the control'lever, the segment I5 is moved to and fro by friction device 2|, as far as the adjustable stop at 22 permits. The stop is arranged so that when the control lever starts to move to the right, i. e. when the throttle valve 20 is being closed, the bore I6 immediately comes into register with the bore 80., i. e. the suction conduit is connected with a. float chamber E. During the movement of the control lever towards the left, i. e. the opening of the throttle, 25 the segment I5 immediately moves to the left against the stop 22. This movement of segment l5 moves the bore I6 to the position indicated in dotted lines in Fig. 3A out of register with bore 8a,. whereby the vacuum connection to float 30 chamber E is interrupted.

The arrangements shown in Figs. 1, 3 and 3A correspond to the first-mentioned manner of carrying out the invention whereby the pressure within the fuel or float chamber is altered. 35

The same arrangements might be used for carrying outthe invention in accordance withthe fourth-mentioned manner of carrying out the invention by introducing additional air into the induction pipeat a point beyond the fuel nozzle. 40 In this case the conduit 4 (Fig. 1) and the conduit I8 (Fig. 3) would not be connected with the fuel or float chamber, but would terminate freely to the atmosphere so that fresh air would enter the induction pipe at each initial closing 45 movement of the throttle valve. In this way the conduits 3, 4 (Figs. 1 and 2) and the conduits IB, I6, 8a (Figs. 3, 3A) would form a second air conduit. The fresh air entering through this conduit would partially equalize the vacuum created by the motor and reduce in this way the vacuum at the fuel nozzle and hence the quantity of fuel introduced.

The arrangement shown in Figs. 4, 4A and 43 corresponds to the second-mentioned manner of 5 carrying out the invention. In this case a drag mechanism comprising a segment 23 is loosely mounted on the shaft of the throttle valve. The segment 23 carries a needle 21, the end of which projects into the fuelchannel F and which moves 60 up and down upon an oscillating movement of the segment 23. The segment 23 is actuated by the throttle lever 24 through a spring-loaded fric-' tion mechanism :5 which shifts the segment 23 until a projecting portion thereof engages the stationary stop 26, the movement being in the same direction as the movement of lever 24. In this way a drag mechanism is obtained by which -.the needle 21 is operated. When the throttle valve performs a closing movement, the needle '21 immediately moves down and reduces the free .cross section of the fuel channel. When the quantity is increased, the fuel supply is corre-' spondingly reduced and vice versa. In accordance with the invention use is made of this fact by providing an'air conduit 36, comprising passage 31 having two inlet branches 38 and 39 having openings 33 and 34 respectively, of predetermined exact sizes. Branch 38 is controlled by a valve 3| and is supplied with air through an opening 32'. The opening 34 of branch 39 is of such size that it allows only the entrance of such an air quantity that a rich mixture is obtained. If, however, the opening 33 is open in addition to the opening 34, the quantity of correction or supplemental air is so large that only a small quantity of fuel is supplied to the fuel nozzle, whereby a lean mixture is obtained. The opening 34 is always open, while the opening 33 is closed by the valve 3| upon an initial opening.

movement of the throttle valve and opened upon an initial closing movement of the throttle valve. The'opening and closing of the valve 3| is effected by the arm 3000f a drag'mechanism comprising a segment loosely mounted on the shaft of the throttle valve and actuated by the lever 28 of the latter through a friction mechanism 29. During an initial closing movement of the throttle valve, the valve 3| is raised until the segment strikes against the stop 35. During the initial opening of the throttle valve, the valve 3| is closed.

. rangedat a substantial distance from the correction air nozzle. It'is, for instance, possible to use an arrangement such as that shown in Fig. 1

a in which the conduit 3 is connected to the tubular piece ll shown; in Fig. 6 while the conduit 4 terminates in the atmosphere.

All above-described arrangements serve the purpose of producing, during the closing movement of the throttle valve, a poorer mixture, and at the opening movement, a richer mixture.

It is advisable to provide for regulation of the economizing effect in order that the economizing device can be adapted to different atmospheric conditions particularly to different atmospheric pressure. This is of particular importance in case of aeroplanes. With the arrangement shown in Fig. 1, for instance, a'regulation of the equalizing opening is possible either by hand or automatica11y,by diaphragms.

I claim:

1. In a carburetor forinternal combustion engines, in combination an air induction conduit for connection with an engine, a throttle valve in said conduit, a fuel nozzle opening into said conduit, a'fuel chamber, a fuel conduit connecting the fuel chamber'and the said fuel nozzle, means for changing the position of said throttle valve, means for enriching or weakening the fuel air mixture according-to the direction of movement of the throttle, said means being moved to a position of adjustment upon an initial movement of the said throttle valve in one direction and to an opposite position of adjustment upon an initial movement opposite to the direction of its preceding movement.

' 2. In a carburetor control mechanism, said carburetor having a float chamber and a throttle valve, an operating gear connected with said valve, an induction pipe connected with the lower part of the float chamber, a conduit connecting the induction pipe and the upper part of the float chamber, a control device in said conduit connected with the operating gear to interrupt communication between the induction pipe and the float chamber through said conduit by an initial opening movement of the operating gear and open said communicatim by an initial closing movement of said gear.

3. In a carburetor control mechanism, said carburetor having a-float chamber and a throttle valve, an operating gear connected with said valve,

an induction pipe connected with the lower part of the float chamber, a conduit connected with the induction pipe, said connection having a plurality of channels opening into different pressure zones in the vicinity of the throttle valve opening, said'conduit being connected with the upper part of the float chamber, a control device in said conduit connected with the operating gear to inter-* rupt communication between the induction pipe and float chamber through said conduit by an initial opening movement of the operating gear and open said communication by an initial closing movement of said gear.

4. In a carburetor control mechanism for internal combustion engines, said carburetor having a float chamber, an induction pipe, a throttle valve in said pipe, operating gear for controlling the position of said valve and having means'connected therewith for influencing the composition of. the fuel air mixture, said means comprising a drag mechanism actuated by movement of the throttle operating gear, a conduit'connected with the induction pipe and the upper part of the float chamber, the connection of said'conduit with the induction pipe comprising a plurality of orifices opening into different zones in the vicinity of the throttle opening, said drag mechanism having means to open said conduit by the initial part of a closing movement of the operating gear and to close said conduit by the initial part of an opening movement of said gear.

5. A mixture control device for carburetors for internal combustion engines, comprising in combination, a carburetor, a throttle element of said carburetor, means for changing the position of said element, means for influencing the composition of the fuel air mixture, comprisinga drag mechanism actuated by movement of said throttle element, and a regulating-valve actuated by said drag mechanism to regulate the fuel mixture so that during the initial opening movement of the said throttle element the fuel feed is increased and during the initial closing movement of said throttle element the fuel feed is reduced. 6. In a carburetor for "internal combustion engines, an air conduit, a fuel nozzle opening in the air conduit, a throttle valve in said conduit, 65 mechanism for operating the throttle valve, a fuel chamber, a' fuel conduit connecting the fuel nozzle to a fuel chambena second air conduit opening into the-fuel conduit, means operated by the throttle operating mechanism for'increasing the cross sectional area of said second air conduit upon an initial movement of the throttle operating mechanism in one direction and for maintaining the said increased cross sectional area upon continued movement in said direction and Y for reducing the cross sectional area of said second air conduit upon an initial movement of said operating mechanism in the opposite direction and for retaining said reduced cross sectional area upon continued movement in the said opposite direction.

7. A mixture control device for carburetors for internal combustion engines, comprising in combination a carburetor, a throttle element of said carburetor, means for changing the position of said element, a supplemental air supply conduit, means for influencing the composition of the fuel air mixture comprising a drag mechanism actuated by movement of said means for changing the position of the throttle element, a regulating valve actuated by said drag mechanism to regulate the supplemental air supply so that during the initial closing movement of said throttle element the supplemental air is increased and during the initial opening movement of said throttle element the supplemental air is reduced.

8. In a carburetor for internal combustion engines, an air conduit, a fuel nozzle opening in the air conduit, a throttle valve in said conduit, mechanism for operating the throttle valve, a second air conduit opening in the first-mentioned conduit beyond the fuel nozzle, means operated by 'the throttle operating mechanism for opening said second conduit upon an initial movement of the throttle operating mechanism in one direction and for maintaining said conduit open upon continued movement in said direction, means for closing said conduit upon movement of said operating mechanism in the opposite direction and for retaining said conduit closed upon continued movement in the said opposite direction.

9. A mixture control device for carburetors for internal combustion engines, comprising in combination, a carburetor, a throttle element of said carburetor, means'for changing the position of said element and influencing the composition of the fuel air mixture, said means including a drag mechanism adapted to be actuated by an initial movement of said throttle element, an induction pipe of the engine and a conduit between said pipe and the atmosphere adapted to be opened by said mechanism during an initial closing movement of said throttle element and to be closed during an initial opening movement of said throttle element.

10. In a carburetor for internal combustion engines, an air conduit having a venturi, a fuel nozzle opening in said air conduit in the effective zone of the venturi, a throttle valve in said conduit, mechanism for operating the throttle valve, a second air conduit opening into the first-mentioned conduit beyond the venturi, means operated by the throttle operating mechanism for opening said second conduit upon an initial movement of the throttle operating mechanism in one direction, for maintaining said conduit open upon continued movement in said direction, for closing said conduit upon movement of said operating mechanism in the opposite direction and for retaining said conduit closed upon continued movement'in the said opposite direction.

11. In a carburetor for internal combustion engines, an air conduit, a throttle valve in said mentioned air conduit, a stop limiting the movement of the second-mentioned valve when in open position, and a frictional engagement between the throttle operating mechanism and the second-mentioned valve for opening said second- 5 mentioned valve upon movement of said mechanism in one direction and permitting further ,movement of said operating mechanism in the same direction without further movement of said second-mentioned valve, and.- for closing said sec- 10 ond-mentioned valve by the initial movement of said mechanism in the opposite direction while permitting further movement in said opposite direction without affecting said second-mentioned valve. l5

12. Fuel supply mechanism for internal combustion engines comprising a carburetor having an induction pipe, a throttle valve in said pipe, operating gearfor controlling the position of said valve, mixture regulating mechanism including valve means having a yielding coupling with the throttle operating gear to richen the fuel mixture during the initial part of an opening movement of the operating gear and retain the richened mixture during further opening movement, and to weaken the mixture during the initial part of a closing movement of the operating gear and reta n the weakened mixture during further closing movement of the gear.

13. A mixture control device for carburetors for-internal combustion engines, comprising in combination a carburetor, a throttle element of said carburetor, a control mechanism for regulating the fuel-air mixture yieldingly connected to said throttle element, and means on said carburetor for changing the position of said throttle element and for actuating said mixture control mechanism, said means starting the regulation of the mixture at its initial movement and completing the regulation during the initial part of a movement .of the throttle element.

14. In a carburetor for internal combustion engines, an induction pipe for supplying a hydrocarbon-air mixture to the engine, means for regulating the quantity of mixture supplied to the engine, means for regulating the composition of, the mixture in accordance with the quantity regulation to enrich the mixture upon an initial increase of the quantity and-maintain the enriched composition while the quantity is being increased and to lean the mixture upon an initial reduction of quantity and to maintain the leaned mixture while the quantity is being reduced.

15. In a carburetor for internal combustion engines, an induction pipe for supplying a hydrocarbon-air mixture to the engine, means for regulating the quantity of mixture supplied to the engine, operating gear for said quantity regulating means, means controlled by said operating gear to regulate the composition of the mixture to enrich the mixture upon an initial movement of said gear in the direction to increase the quantity and to maintain the enriched mixture during the following increasing movement of said gear and to lean the mixture upon an initial movement of said gear in the direction to reduce the quantity and to maintain the leaned mixture during the following reducing movement of the gear.

CARL SCHMIQ- 

